Multilayer rigid flexible printed circuit board and method for manufacturing the same

ABSTRACT

The present invention provides a multilayer rigid flexible printed circuit board including: a flexible region including a flexible film having a circuit pattern formed on one or both surfaces thereof and a laser blocking layer formed on the circuit pattern; and a rigid region formed adjacent to the flexible region and including a plurality of pattern layers on one or both surfaces of extended portions extended to both sides of the flexible film of the flexible region, and a method for manufacturing the same.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 16/438,755filed on Jun. 12, 2019 which is a continuation of application Ser. No.15/398,803 filed on Jan. 5, 2017, now U.S. Pat. No. 10,368,445, which isa continuation of application Ser. No. 14/024,115 filed on Sep. 11,2013, now U.S. Pat. No. 9,743,529, which is a continuation ofapplication Ser. No. 12/923,994 filed on Oct. 19, 2010, now U.S. Pat.No. 8,558,116, which claims the benefit under 35 USC 119(a) of KoreanPatent Application No. 10-2009-0102783 filed on Oct. 28, 2009, in theKorean Intellectual Property Office, the entire disclosures of which areincorporated herein by reference for all purposes.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a multilayer rigid flexible printedcircuit board and a method for manufacturing the same, and moreparticularly, to a multilayer rigid flexible printed circuit boardmanufactured by a rigid build-up substrate manufacturing method afterforming a laser stopper in a flexible region, and a method formanufacturing the same.

2. Description of the Related Art

A printed circuit board (PCB) is a circuit board which plays a role ofelectrically connecting or mechanically fixing predetermined electroniccomponents and consists of an insulating layer made of a phenol resin oran epoxy resin and a copper foil layer attached to the insulating layerand having a predetermined wiring pattern formed thereon.

At this time, the PCBs are classified into a single-sided PCB in whichwiring is formed only on one surface of an insulating layer, adouble-sided PCB in which wirings are formed on both surfaces of aninsulating layer, and a multilayer PCB in which wirings are formed in aplurality of layers, according to the number of stacked layers.

Recently, a multilayer printed circuit board, particularly, a rigidflexible printed circuit board (RFPCB) having flexibility has been atthe center of a printed circuit board market due to miniaturization,thickness reduction, and high density of electronic products, and marketinterest in this has been increased.

The RFPCB includes a flexible region in which a circuit pattern isformed on a polyester or polyimide (PI) flexible film having flexibilityand a rigid region in which an insulating layer is stacked on theflexible film to increase physical hardness.

This RFPCB has been used in devices requiring a high density circuitdesign such as notebooks, digital cameras, camcorders, and mobilecommunication terminals since it enables three dimensional wiring and iseasily assembled.

SUMMARY OF THE INVENTION

The present invention has been proposed in order to solve theabove-described problems, and it is, therefore, an object of the presentinvention to provide a multilayer rigid flexible printed circuit boardcapable of manufacturing both a flexible region and a rigid region by arigid build-up manufacturing process after forming a laser stopper inthe flexible region, and a method of manufacturing the same.

In accordance with an aspect of the present invention to achieve theobject, there is provided a multilayer rigid flexible printed circuitboard including: a flexible region including a flexible film having acircuit pattern formed on one or both surfaces thereof and a laserblocking layer formed on the circuit pattern; and a rigid region formedadjacent to the flexible region and including a plurality of patternlayers on one or both surfaces of extended portions extended to bothsides of the flexible film of the flexible region.

Further, the laser blocking layer of the multilayer rigid flexibleprinted circuit board in accordance with the present invention mayinclude an adhesive coated on the circuit pattern formed on the flexiblefilm, a polyimide layer formed on the adhesive to protect the circuitpattern, and a copper foil layer formed on the polyimide layer.

Further, the laser blocking layer of the multilayer rigid flexibleprinted circuit board in accordance with the present invention mayinclude an adhesive coated on the circuit pattern formed on the flexiblefilm, a polyimide layer formed on the adhesive to protect the circuitpattern, an adhesive disposed on the polyimide layer, and a copper foillayer formed on the adhesive.

Further, the multilayer rigid flexible printed circuit board inaccordance with the present invention may further include anelectromagnetic shielding layer which is formed between the laserblocking layer and the flexible film having the circuit pattern formedthereon.

Further, the electromagnetic shielding layer of the multilayer rigidflexible printed circuit board in accordance with the present inventionmay include an adhesive coated on the circuit pattern formed on theflexible film, a polyimide layer formed on the adhesive to protect thecircuit pattern, and a copper foil layer formed on the polyimide layer.

Further, the electromagnetic shielding layer of the multilayer rigidflexible printed circuit board in accordance with the present inventionmay include an adhesive coated on the circuit pattern formed on theflexible film, a polyimide layer formed on the adhesive to protect thecircuit pattern, an adhesive disposed on the polyimide layer, and acopper foil layer formed on the adhesive.

Further, the rigid region of the multilayer rigid flexible printedcircuit board in accordance with the present invention may furtherinclude at least one inner circuit pattern which is formed between theplurality of pattern layers to be electrically connected to the circuitpattern.

Further, the rigid region of the multilayer rigid flexible printedcircuit board in accordance with the present invention may furtherinclude an outer circuit pattern which is formed on the outermost uppersurface of the plurality of pattern layers to be electrically connectedto the circuit pattern.

Further, the laser blocking layer or the electromagnetic shielding layerof the multilayer rigid flexible printed circuit board in accordancewith the present invention may be extended to a region where at leastone of a via hole and a through hole of the plurality of pattern layersis formed.

In accordance with another aspect of the present invention to achievethe object, there is provided a method for manufacturing a multilayerrigid flexible printed circuit board including the steps of: providing abase substrate including a flexible film having a circuit pattern formedon one or both surfaces thereof; forming a laser blocking layer toprotect the circuit pattern of a flexible region of the base substrate;stacking a plurality of pattern layers on at least one surface of thebase substrate having the laser blocking layer formed thereon; formingcopper foil layers on upper surfaces of the plurality of pattern layerswhile interposing insulators therebetween and stacking an outer patternlayer having a via hole or a through hole formed therein; performinglaser processing by forming windows in the via hole or the through holeof the outer pattern layer and the flexible region; and forming an outercircuit pattern by performing copper plating on the laser-processedouter pattern layer and etching portions of the copper plating layer.

Further, the step of providing the base substrate including the flexiblefilm having the circuit pattern formed on the one or both surfacesthereof of the method for manufacturing the multilayer rigid flexibleprinted circuit board in accordance with the present invention mayinclude the steps of providing the flexible film having a copper foillayer stacked on one or both surfaces thereof and forming the circuitpattern by etching the copper foil layer.

Further, the step of forming the laser blocking layer to protect thecircuit pattern of the flexible region of the base substrate of themethod for manufacturing the multilayer rigid flexible printed circuitboard in accordance with the present invention may include the steps ofcoating an adhesive in the flexible region of the base substrate,forming a polyimide layer on the adhesive, and forming a copper foillayer on the polyimide layer.

Further, the step of forming the laser blocking layer to protect thecircuit pattern of the flexible region of the base substrate of themethod for manufacturing the multilayer rigid flexible printed circuitboard in accordance with the present invention may include the steps ofcoating an adhesive in the flexible region of the base substrate,forming a polyimide layer on the adhesive, disposing an adhesive on thepolyimide layer, and forming a copper foil layer on the adhesive.

Further, in the step of stacking the plurality of pattern layers on theat least one surface of the base substrate having the laser blockinglayer formed thereon of the method for manufacturing the multilayerrigid flexible printed circuit board in accordance with the presentinvention, the plurality of pattern layers may be formed by repeatingthe step of forming one pattern layer including the steps of forming acopper foil layer while interposing at least one insulator and forming avia hole or a through hole in the insulator having the copper foil layerformed thereon and forming a circuit pattern by forming a copper platinglayer on an upper surface of the insulator having the via hole or thethrough hole formed therein and etching portions of the copper platinglayer.

Further, the step of performing the laser processing by forming thewindows in the via hole or the through hole of the outer pattern layerand the flexible region of the method for manufacturing the multilayerrigid flexible printed circuit board may include the steps of formingcopper foil openings in the via hole or the through hole of the outerpattern layer and the flexible region by window etching and removing theinsulator by irradiating laser through the copper foil openings.

In accordance with still another aspect of the present invention toachieve the object, there is provided a method for manufacturing amultilayer rigid flexible printed circuit board including the steps of:providing a base substrate including a flexible film having a circuitpattern formed on one or both surfaces thereof; forming anelectromagnetic shielding layer on the one or both surfaces of theflexible film having the circuit pattern formed thereon to protect thecircuit pattern and shield electromagnetic waves; forming a laserblocking layer on the electromagnetic shielding layer or on the flexiblefilm on which the electromagnetic shielding layer is not formed;stacking a plurality of pattern layers on one or both surfaces of thebase substrate having the laser blocking layer formed thereon; formingcopper foil layers on upper surfaces of the plurality of pattern layerswhile interposing insulators therebetween and stacking an outer patternlayer having a via hole or a through hole formed therein; performinglaser processing by forming windows in the via hole or the through holeof the outer pattern layer and a flexible region; and forming an outercircuit pattern by performing copper plating on the laser-processedouter pattern layer and etching portions of the copper plating layer.

Further, in the step of forming the laser blocking layer on theelectromagnetic shielding layer or on the flexible film on which theelectromagnetic shielding layer is not formed of the method formanufacturing the multilayer rigid flexible printed circuit board inaccordance with the present invention, the laser blocking layer may beformed on one or both surfaces of the base substrate.

Further, in the step of forming the electromagnetic shielding layer onthe one or both surfaces of the flexible film having the circuit patternformed thereon to protect the circuit pattern and shield theelectromagnetic waves of the method for manufacturing the multilayerrigid flexible printed circuit board in accordance with the presentinvention, the electromagnetic shielding layer may be formed on one orboth surfaces with respect to the base substrate.

Further, the step of providing the base substrate including the flexiblefilm having the circuit pattern formed on the one or both surfacesthereof of the method for manufacturing the multilayer rigid flexibleprinted circuit board in accordance with the present invention mayinclude the steps of providing the flexible film having a copper foillayer stacked on one or both surfaces thereof and forming the circuitpattern by etching portions of the copper foil layer.

Further, the step of forming the laser blocking layer or theelectromagnetic shielding layer of the method for manufacturing themultilayer rigid flexible printed circuit board in accordance with thepresent invention may include the steps of disposing an adhesive in theflexible region of the base substrate, forming a polyimide layer on theadhesive layer, and forming a copper foil layer on the polyimide layer.

Further, the step of forming the laser blocking layer or theelectromagnetic shielding layer of the method for manufacturing themultilayer rigid flexible printed circuit board in accordance with thepresent invention may include the steps of disposing an adhesive in theflexible region of the base substrate, forming a polyimide layer on theadhesive, disposing an adhesive on the polyimide layer, and forming acopper foil layer on the adhesive.

Further, the step of performing the laser processing by forming thewindows in the via hole or the through hole of the outer pattern layerand the flexible region of the method for manufacturing the multilayerrigid flexible printed circuit board in accordance with the presentinvention may include the steps of forming copper foil openings in thevia hole or the through hole of the outer pattern layer and the flexibleregion by window etching and removing the insulator by irradiating laserthrough the copper foil openings.

Further, the laser blocking layer or the electromagnetic shielding layerof the method for manufacturing the multilayer rigid flexible printedcircuit board in accordance with the present invention may be extendedto a region where at least one of a via hole and a through hole of thepattern layer is formed.

Further, a via hole formed in the electromagnetic shielding layer of themethod for manufacturing the multilayer rigid flexible printed circuitboard in accordance with the present invention may be formed to an upperportion of the copper foil layer of the electromagnetic shielding layer,and a through hole formed in the laser blocking layer and theelectromagnetic shielding layer may be formed through theelectromagnetic shielding layer, the laser blocking layer, and the basesubstrate.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the present generalinventive concept will become apparent and more readily appreciated fromthe following description of the embodiments, taken in conjunction withthe accompanying drawings of which:

FIGS. 1 to 3 are views showing a cross section of a multilayer rigidflexible printed circuit board in accordance with a first embodiment ofthe present invention;

FIGS. 4a and 4b are views showing a cross section of a laser blockinglayer in accordance with an embodiment of the present invention;

FIG. 5 is a view showing a cross section of a laser blocking layer inaccordance with another embodiment of the present invention;

FIGS. 6a and 6b are views showing various embodiments of a stackedstructure of a laser blocking layer and an electromagnetic shieldinglayer in accordance with an embodiment of the present invention;

FIGS. 7a and 7b are views showing various embodiments of a stackedstructure of a laser blocking layer and an electromagnetic shieldinglayer in accordance with another embodiment of the present invention;

FIGS. 8a to 8j are views showing a method for manufacturing a multilayerrigid flexible printed circuit board in accordance with an embodiment ofthe present invention;

FIG. 9 is a view showing a cross section of a multilayer rigid flexibleprinted circuit board in accordance with a second embodiment of thepresent invention; and

FIG. 10 is a view showing a cross section of a multilayer rigid flexibleprinted circuit board in accordance with a third embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As the invention allows for various changes and numerous embodiments,particular embodiments will be illustrated in the drawings and describedin detail in the written description. However, this is not intended tolimit the present invention to particular modes of practice, and it isto be appreciated that all changes, equivalents, and substitutes that donot depart from the spirit and technical scope of the present inventionare encompassed in the present invention.

A multilayer rigid flexible printed circuit board and a method formanufacturing the same in accordance with certain embodiments of thepresent invention will be described below in detail with reference tothe accompanying drawings. Those components that are the same or are incorrespondence are rendered the same reference numeral regardless of thefigure number, and redundant explanations are omitted.

Multilayer Rigid Flexible Printed Circuit Board

A multilayer rigid flexible printed circuit board in accordance with thepresent invention includes a flexible region F and a rigid region R. Theflexible region F is a region which is made of a flexible material andwhere a bending portion is formed. The rigid region is a region which ismade of a rigid material.

The flexible region F includes at least one flexible film having a firstcircuit pattern formed on at least one surface thereof, and a laserblocking layer may be formed on at least one surface of the firstcircuit pattern.

Further, an electromagnetic shielding layer may be further formed on thelaser blocking layer of the flexible region F to shield electromagneticwaves.

The rigid region R is formed adjacent to the flexible region F and mayinclude a plurality of pattern layers on at least one surface of anextended portion of the at least one flexible film.

Hereafter, various embodiments of the multilayer rigid flexible printedcircuit board in accordance with the present invention will bespecifically described.

<Multilayer Rigid Flexible Printed Circuit Board>

First Embodiment

FIGS. 1 to 3 are views showing a cross section of a multilayer rigidflexible printed circuit board in accordance with a first embodiment ofthe present invention.

As shown in FIGS. 1 to 3, a multilayer rigid flexible printed circuitboard in accordance with a first embodiment of the present inventionincludes a flexible region F and a rigid region R, and a laser blockinglayer 50 is formed in the flexible region F.

The laser blocking layer 50 is formed on a base substrate 10 in theflexible region F, and a plurality of pattern layers 20, 30, and 40 areformed on the base substrate 10 in the rigid region R.

First, when describing a structure of the flexible region F, theflexible region F has the structure in which the laser blocking layer 50is formed on the base substrate 10.

The base substrate 10 includes at least one flexible film 11 having afirst circuit pattern 12 formed on at least one surface thereof, and thelaser blocking layer 50 is formed on at least one surface of the firstcircuit pattern 12.

The laser blocking layer 50 includes an adhesive 51, a polyimide layer52, and a copper foil layer 53, and the adhesive 51 is disposed on thefirst circuit pattern 12.

The polyimide layer 52 is formed to protect the first circuit pattern12, the polyimide layer 52 and the first circuit pattern 12 are formedwhile interposing the adhesive 51 therebetween, and the copper foillayer 53 is formed on the polyimide layer 52.

After copper plating 43 is performed on the copper foil layer 53 of thelaser blocking layer 50 to form an outer layer circuit pattern, theouter layer circuit pattern is formed by etching portions of the copperplating 43 in correspondence to the circuit pattern (referring to FIGS.2 and 3).

The laser blocking layer 50 may be formed in various embodiments andwill be described in detail in FIGS. 4a, 4b , and 5 b.

Further, the layer blocking layer 50 may be extended to the rigid regionR.

For example, each side surface of the copper foil layer 53 of the laserblocking layer 50 may be formed smaller than that of the polyimide layer52 formed on a lower surface of the copper coil layer 53 by more than 10μm or the laser blocking layer 50 may be extended to the rigid region Rfrom a boundary surface between the flexible region F and the rigidregion R by 0.05 to 5 mm.

Next, the rigid region R is formed adjacent to the flexible region F andincludes a plurality of pattern layers 20, 30, and 40 on at least onesurface of an extended portion of the at least one flexible film 11.

Generally, one pattern layer is formed by sequentially stacking aninsulator and a copper foil layer on a lower pattern layer, forming avia hole or a through hole in the insulator and the copper foil layer,performing copper plating on the insulator and the copper foil layerhaving the via hole or the through hole formed therein, and etching theinsulator and the copper foil layer according to a circuit pattern.

Here, the insulator may be prepreg or a rigid material, and the copperfoil layer may be formed by a casting, laminating, or sputtering method.

The via hole is a plated through hole formed on the insulator which isformed under the copper foil layer to be electrically connected to thelower circuit pattern, and the plated through hole passes through thebase substrate to be electrically connected to the circuit patternformed at an opposite side of the base substrate.

The via hole or the through hole is a plated through hole formed bycomputer numerical control (CNC) drilling or laser drilling toelectrically connect an outer layer circuit pattern and an inner layercircuit pattern.

The multilayer rigid flexible printed circuit board in accordance withthe present invention includes the plurality of pattern layers 20, 30,and 40 and a plurality of via holes A and B or through holes C and D forelectrically connecting outer circuit patterns 42 and 43 and innercircuit patterns 12, 22, 23, 32, and 33.

Second Embodiment

FIG. 9 is a view showing a cross section of a multilayer rigid flexibleprinted circuit board in accordance with a second embodiment of thepresent invention.

As shown in FIG. 9, a multilayer rigid flexible printed circuit board inaccordance with a second embodiment of the present invention includes aflexible region F and a rigid region R, and a laser blocking layer 50and an electromagnetic shielding layer 60 are formed in the flexibleregion F.

The other components are the same as those of a multilayer rigidflexible printed circuit board in accordance with a first embodiment,and only the components different from those of the multilayer rigidflexible printed circuit board in accordance with a first embodimentwill be described in detail.

The multilayer rigid flexible printed circuit board in accordance with asecond embodiment has a structure in which the electromagnetic shieldinglayer 60 is further formed in a stacked structure of the multilayerrigid flexible printed circuit board in accordance with a firstembodiment.

That is, the laser blocking layer 50 and the electromagnetic shieldinglayer 60 are formed on a base substrate 10 in the flexible region F, anda plurality of pattern layers 20, 30, and 40 are formed on the basesubstrate 10 in the rigid region R.

The laser blocking layer 50 may be formed on one surface of asingle-sided printed circuit board or on both surfaces of a double-sidedprinted circuit board.

The electromagnetic shielding layer 60 may be formed between the laserblocking layer 50 and a flexible film 11 of the single-sided printedcircuit board or between the both laser blocking layers 50 and theflexible film 11 of the double-sided printed circuit board (referring toFIG. 9).

Specifically, the flexible region F has a structure in which theelectromagnetic shielding layer 60 is formed on the base substrate 10,and the base substrate 10 includes the at least one flexible film 11having a first circuit pattern 12 formed on at least one surfacethereof.

The electromagnetic shielding layer 60 is formed on at least one or bothsurfaces of the first circuit pattern 12, and the laser blocking layer50 is formed on the electromagnetic shielding layer 60 or on theflexible film 11 where the electromagnetic shielding layer 60 is notformed.

The laser blocking layer 50 or the electromagnetic shielding layer 60includes an adhesive 51 or 61, a polyimide layer 52 or 62, and a copperfoil layer 53 or 63, and the adhesive 51 or 61 is disposed on the firstcircuit pattern 12.

The polyimide layer 52 is formed to protect the first circuit pattern12, the polyimide layer 52 and the first circuit pattern 12 are formedwhile interposing the adhesive 51 therebetween, and the copper foillayer 53 is formed on the polyimide layer 52.

After copper plating 43 is performed on the copper foil layer 53 of thelaser blocking layer 50 to form an outer layer circuit pattern, theouter layer circuit pattern is formed by etching portions of the copperplating 43 in correspondence to the circuit pattern (referring to FIG.9).

A stacked structure of the laser blocking layer 50 or theelectromagnetic shielding layer 60 may be formed in various embodimentsand will be described in detail in FIGS. 6a, 6b, 7a , and 7 b.

The laser blocking layer 50 or the electromagnetic shielding layer 60may be extended to the rigid region R, and the laser blocking layer 50or the electromagnetic shielding layer 60 extended to the rigid region Ris not removed by laser processing.

For example, the laser blocking layer 50 or the electromagneticshielding layer 60 may be extended to the rigid region R from a boundarysurface between the flexible region F and the rigid region R by 0.05 to5 mm.

Third Embodiment

FIG. 10 is a view showing a cross section of a multilayer rigid flexibleprinted circuit board in accordance with a third embodiment of thepresent invention.

As shown in FIG. 10, a multilayer rigid flexible printed circuit boardin accordance with a third embodiment of the present invention includesa flexible region F and a rigid region R, and a laser blocking layer 50and an electromagnetic shielding layer 60 are formed in the flexibleregion F.

The other components are the same as those of a multilayer rigidflexible printed circuit board in accordance with a first embodiment,and only the components different from those of the multilayer rigidflexible printed circuit board in accordance with a first embodimentwill be described in detail.

The multilayer rigid flexible printed circuit board in accordance with athird embodiment has a structure in which the electromagnetic shieldinglayer 60 is further formed in a stacked structure of the multilayerrigid flexible printed circuit board in accordance with a firstembodiment, and a via hole A or a through hole C is formed in the laserblocking layer 50 and the electromagnetic shielding layer 60.

The flexible region F has a structure in which the electromagneticshielding layer 60 is formed on a base substrate 10, and the basesubstrate 10 includes at least one flexible film 11 having a firstcircuit pattern 12 formed on at least one surface thereof.

The electromagnetic shielding layer 60 is formed on at least one or bothsurfaces of the first circuit pattern 12, and the laser blocking layer50 is formed on the electromagnetic shielding layer 60 or on theflexible film 11 where the electromagnetic shielding layer 60 is notformed.

The laser blocking layer 50 or the electromagnetic shielding layer 60includes an adhesive 51 or 61, a polyimide layer 52 or 62, and a copperfoil layer 53 or 63, and the adhesive 61 is disposed on the firstcircuit pattern 12.

The polyimide layer 62 of the electromagnetic shielding layer 60 isformed to protect the first circuit pattern 12, the polyimide layer 62and the first circuit pattern 12 are formed while interposing theadhesive 61 therebetween, and the copper foil layer 63 is formed on thepolyimide layer 62.

After copper plating 43 is performed on the copper foil layer 53 of thelaser blocking layer 50 to form an outer layer circuit pattern, theouter layer circuit pattern is formed by etching portions of the copperplating 43 in correspondence to the circuit pattern (referring to FIG.10).

A stacked structure of the laser blocking layer 50 or theelectromagnetic shielding layer 60 may be formed in various embodimentsand will be described in detail in FIGS. 6a, 6b, 7a , and 7 b.

The laser blocking layer 50 or the electromagnetic shielding layer 60may be extended to the rigid region R.

The laser blocking layer 50 or the electromagnetic shielding layer 60extended to the rigid region R is not removed by laser processing, andthe via hole A or the through holes C and D formed in the rigid region Rpass through some or all of the laser blocking layer 50 and theelectromagnetic shielding layer 60.

For example, as shown in FIG. 10, a second circuit pattern 23 formed ona fifth pattern layer 20 may be electrically grounded by being connectedto the copper foil layer 63 of the electromagnetic shielding layer 60through the via hole A.

Further, the second circuit pattern 23 formed on the fifth pattern layer20 may be connected to a second circuit pattern 23 formed on a thirdpattern layer 20 by passing through the electromagnetic shielding layer60 and the laser blocking layer 50 through the through holes C and D.

That is, the through holes C and D can ground the circuit patterns ofthe upper and lower pattern layers with respect to the base substrate10.

<Laser Blocking Layer>

FIGS. 4a, 4b , and 5 are views showing various embodiments of a laserblocking layer.

First Embodiment

As shown in FIG. 4a , a laser blocking layer 50 in accordance with afirst embodiment of the present invention is formed in a three-layerstructure including an adhesive 51, a polyimide layer 52, and a copperfoil layer 53.

The polyimide layer 52 is formed to protect a circuit pattern, and thepolyimide layer 52 and the circuit pattern are formed while interposingthe adhesive 51 therebetween, and the copper foil layer 53 is formed onthe polyimide layer 52.

Second Embodiment

As shown in FIG. 4b , a laser blocking layer 50 in accordance with asecond embodiment of the present invention is formed in a four-layerstructure including a first adhesive 51 a, a second adhesive 51 b, apolyimide layer 52, and a copper foil layer 53.

It is possible to improve a stacked structure by interposing the firstadhesive 51 a and the second adhesive 51 b between the polyimide layer52 and the circuit pattern and between the polyimide layer 52 and thecopper foil layer 53.

Third Embodiment

As shown in FIG. 5, both ends of a copper foil layer 53 of a laserblocking layer 50 in accordance with a third embodiment of the presentinvention are formed shorter than both ends of a polyimide layer 52.

That is, the both ends of the polyimide layer 52 of a flexible region Fare extended to a rigid region R, and the copper foil layer 53 formed onthe polyimide layer 52 is also extended to the rigid region R.

The above method of forming the laser blocking layer 50 is just oneembodiment, and the laser blocking layer 50 may be formed by variousmethods.

<Electromagnetic Shielding Layer>

FIGS. 6a, 6b, 7a, and 7b are views showing various embodiments of astacked structure of a laser blocking layer and an electromagneticshielding layer.

First Embodiment

FIG. 6a is a view showing a stacked structure of a three-layer laserblocking layer 50 and a three-layer electromagnetic shielding layer 60,and FIG. 6b is a view showing a stacked structure of a four-layer laserblocking layer 50 and a four-layer electromagnetic shielding layer 60.

The laser blocking layer 50 and the electromagnetic shielding layer 60include adhesives 51 and 61, polyimide layers 52 and 62, and copper foillayers 53 and 63, respectively. The adhesive is disposed on at least one(referring to FIG. 6a ) or both (referring to FIG. 6b ) of upper andlower surfaces of the polyimide layers 52 and 62.

That is, both of the laser blocking layer 50 and the electromagneticshielding layer 60 are formed in three layers of the adhesives 51 and61, the polyimide layers 52 and 62, and the copper foil layers 53 and 63or in four layers of the first adhesives 51 a and 61 a, the polyimidelayers 52 and 62, the second adhesives 51 b and 61 b, and the copperfoil layers 53 and 63.

Further, the laser blocking layer 50 may be formed in three layers, andthe electromagnetic shielding layer 60 may be formed in four layers. Or,the laser blocking layer 50 may be formed in four layers, and theelectromagnetic shielding layer 60 may be formed in three layers.

Second Embodiment

FIG. 7a shows that a copper foil layer 63 of an electromagneticshielding layer 60 is formed shorter than a polyimide layer 62 in astacked structure of the laser blocking layer 50 and the electromagneticshield layer 60 shown in FIG. 6a , and FIG. 7b shows that the copperfoil layer 63 of the electromagnetic shielding layer 60 and a copperfoil layer 53 of the laser blocking layer 50 are formed shorter than thepolyimide layer 52 or 62 of the electromagnetic shielding layer 60 orthe laser blocking layer 50.

The above embodiment is just one embodiment of the present invention,and the stacked structure may be variously formed.

The above method of forming the electromagnetic shielding layer 60 isjust one embodiment, and the electromagnetic shielding layer 60 may beformed by various methods.

Method for Manufacturing Multilayer Rigid Flexible Printed Circuit Board

A method for manufacturing a multilayer rigid flexible printed circuitboard in accordance with the present invention includes the steps ofproviding a base substrate, forming a laser blocking layer, stacking aplurality of pattern layers, and forming an outer pattern layer.

FIGS. 8a to 8j are views showing a method for manufacturing a multilayerrigid flexible printed circuit board in accordance with an embodiment ofthe present invention.

As shown in FIGS. 8a and 8b , in the step of providing a base substrate10, a first circuit pattern 12 is formed by stacking a copper foil layer12 on at least one surface of a flexible film 11 and etching the copperfoil layer 12.

As shown in FIG. 8c , a laser blocking layer 50 is completed by forminga polyimide layer 52 in a flexible region F of the base substrate 10while interposing an adhesive 51 therebetween and forming a copper foillayer 53 on the polyimide layer 52.

Further, the laser blocking layer 50 is completed by forming thepolyimide layer 52 in the flexible region F of the base substrate 10while interposing a first adhesive 51 a therebetween and forming thecopper foil layer 53 on the polyimide layer 52 while interposing asecond adhesive 51 b therebetween.

At this time, each side surface of the copper foil layer formed on theadhesive may be formed smaller than the polyimide layer formed on alower surface by 10 μm.

Further, the laser blocking layer 50 may be extended to a rigid region Rfrom a boundary surface between the flexible region F and the rigidregion R by 0.05 to 5 mm.

As shown in FIGS. 8d to 8f , in the step of stacking a plurality ofpattern layers 20 and 30, one pattern layer is formed by forming acopper foil layer 22 or 32 while interposing at least one insulator 21or 31, forming via holes A and B or through holes C and D in portions ofthe insulator 21 or 31 or the copper foil layer 22 or 32, and forming acircuit pattern 23 or 33 after performing copper plating on the copperfoil layer 22 or 32 having the via holes A and B or the through holes Cand D formed therein, and the plurality of pattern layers are formed byrepeating the above steps.

As shown in FIGS. 8g to 8j , in the step of forming an outer patternlayer 40, an outer circuit pattern is formed by forming a copper foillayer 42 on the plurality of pattern layers 20 and 30 while interposingat least one insulator 41 therebetween, forming a via hole or a throughhole, forming windows in the via hole or the through hole of the outerpattern layer 40 and the flexible region, and performing laserprocessing on the windows.

Here, the method of forming the outer circuit pattern by forming thewindows and performing the laser processing on the windows forms theouter circuit pattern by forming copper foil openings in the via hole orthe through hole of the outer pattern layer and the flexible regionthrough window etching, irradiating laser through the copper foilopenings to remove the insulator, performing copper plating on the outerpattern layer from which the insulator is removed, and etching portionsof the outer pattern layer.

Further, a method for manufacturing a multilayer rigid flexible printedcircuit board in another embodiment of the present invention can protectdevices from external electromagnetic waves by providing a basesubstrate, forming a laser blocking layer, and further forming anelectromagnetic shielding layer on the laser blocking layer.

In an embodiment of the present invention, since the flexible region ismanufactured without window processing by using materials and equipmentof a rigid build-up substrate, it is possible to achieve processsimplification and cost reduction and minimize scale change. Therefore,there is an effect of utilizing an existing rigid substrate productionline without change.

Further, since general prepreg can be used as the insulator used formanufacturing the rigid flexible printed circuit board instead of noflow prepreg, there are effects of improving filling performance andreducing cost.

Further, since the electromagnetic shielding layer is further provided,there is an effect of minimizing influence of external electromagneticwaves.

Although a few embodiments of the present general inventive concept havebeen shown and described, it will be appreciated by those skilled in theart that changes may be made in these embodiments without departing fromthe principles and spirit of the general inventive concept, the scope ofwhich is defined in the appended claims and their equivalents.

1. A multilayer rigid flexible printed circuit board comprising: aflexible film comprising a first circuit pattern on one or bothsurfaces, and having an area corresponding to a rigid region and aflexible region of the multilayer rigid flexible printed circuit board,the first circuit pattern comprising a first portion in the flexibleregion and a second portion in the rigid region; a first insulatinglayer disposed on the flexible film in the flexible region to cover thefirst portion of the first circuit pattern and having an extensionportion extending into a portion of the flexible film in the rigidregion; a first adhesive disposed between the first circuit pattern andthe first insulating layer; a copper pattern positioned at the rigidregion of the flexible film and disposed on the extension portion of thefirst insulating layer; and a second insulating layer disposed on theflexible film in the rigid region, and comprising a second circuitpattern, wherein at least a portion of the second portion of the firstcircuit pattern is physically isolated from the first adhesive.
 2. Themultilayer rigid flexible printed circuit board according to claim 1,wherein the copper pattern is physically isolated from the first circuitpattern and the second circuit pattern.
 3. The multilayer rigid flexibleprinted circuit board according to claim 1, wherein the first insulatinglayer comprises a polyimide.
 4. The multilayer rigid flexible printedcircuit board according to claim 1, further comprising a second adhesivedisposed between the first insulating layer and the copper pattern. 5.The multilayer rigid flexible printed circuit board according to claim1, wherein the copper pattern is exposed on side surfaces of the firstand the second insulating layers facing the flexible domain. 6-8.(canceled)
 9. The multilayer rigid flexible printed circuit boardaccording to claim 1, wherein the rigid region further comprises atleast one circuit pattern which is formed between a plurality ofinsulating layers to be electrically connected to either one or both ofthe first and the second circuit patterns.
 10. The multilayer rigidflexible printed circuit board according to claim 1, wherein the rigidregion further comprises an outer circuit pattern which is formed on theoutermost upper surface of a plurality of insulating layers to beelectrically connected to either one or both of the first and the secondcircuit patterns.
 11. The multilayer rigid flexible printed circuitboard according to claim 1, further comprising a plurality of conductivevias connecting to either one or both of the first circuit pattern andthe second circuit pattern, wherein the plurality of conductive vias arenot directly connected to the portion of the first circuit patterncovered by the first insulating layer.
 12. The multilayer rigid flexibleprinted circuit board according to claim 1, wherein at least a portionof the first portion of the first circuit pattern is in contact with thefirst adhesive.
 13. The multilayer rigid flexible printed circuit boardaccording to claim 1, wherein, in cross-section view, a total length ofthe first insulating layer in the flexible region is larger than that ofthe extension portion of the first insulating layer in the rigid region.